The present invention relates to methods and apparatuses for transporting a flow of air and particulates through a vacuum cleaner.
Conventional upright vacuum cleaners are commonly used in both residential and commercial settings to remove dust, debris and other particulates from floor surfaces, such as carpeting, wood flooring, and linoleum. A typical conventional upright vacuum cleaner includes a wheel-mounted head which includes an intake nozzle positioned close to the floor, a handle that extends upwardly from the head so the user can move the vacuum cleaner along the floor while remaining in a standing or walking position, and a blower or fan. The blower takes in a flow of air and debris through the intake nozzle and directs the flow into a filter bag or receptacle which traps the debris while allowing the air to pass out of the vacuum cleaner.
One drawback with some conventional upright vacuum cleaners is that the flow path along which the flow of air and particulates travels may not be uniform. and/or may contain flow disruptions or obstructions. Accordingly, the flow may accelerate and decelerate as it moves from the intake nozzle to the filter bag. As the flow decelerates, the particulates may precipitate from the flow and reduce the cleaning effectiveness of the vacuum cleaner and lead to blocking of the flow path. In addition, the flow disruptions and obstructions can reduce the overall energy of the flow and therefore reduce the capacity of a flow to keep the particulates entrained until the flow reaches the filter bag.
Another drawback with some conventional upright vacuum cleaners is that the blowers and flow path can be noisy. For example, one conventional type of blower includes rotating fan blades that take in axial flow arriving from the intake nozzle and direct the flow into a radially extending tube. As each fan blade passes the entrance opening of the tube, it generates noise which can be annoying to the user and to others who may be in the vicinity of the vacuum cleaner while it is in use.
Still another drawback with some conventional upright vacuum cleaners is that the filter bag may be inefficient. For example, some filter bags are constructed by folding over one end of an open tube of porous filter material to close the one end, and leaving an opening in the other end to receive the flow of air and particulates. Folding the end of the bag can pinch the end of the bag and reduce the flow area of the bag, potentially accelerating the flow through the bag. As the flow accelerates through the bag, the particulates entrained in the flow also accelerate and may strike the walls of the bag with increased velocity, potentially weakening or breaking the bag and causing the particulates to leak from the bag.
This invention relates to methods and apparatuses for transporting a flow of air and particulates through a vacuum cleaner, The apparatus can include an airflow propulsion device having a hub rotatable about a hub axis and a plurality of vanes depending from the hub and extending in a generally radial direction away from the hub axis. Adjacent vanes define a flow passage therebetween and each flow passage can have an approximately constant flow area from a first region proximate to the hub axis to a second region proximate to the vane outer edges.
In one embodiment, the air flow propulsion device includes a housing having a single inlet aperture and two outlet apertures spaced apart from the inlet aperture. In a further aspect of this embodiment, the vanes can be arranged such that when one vane is approximately centered on one of the outlet apertures, the vane closest to the other outlet aperture is offset from the center of the other outlet aperture. In still another embodiment of the invention, the vanes can be rotated relative to the housing at a rate of approximately 7,700 rpm to move a flow of approximately 132 cfm through the housing. The performance of the airflow propulsion device can accordingly be at least as great when installed in a vacuum cleaner as when uninstalled.